Topical drug preparations

ABSTRACT

Topical gelled compositions comprising an optional drug dispersed within a polymer matrix, methods of producing the same and treatments with the complex.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 08/796,578, filed Feb. 6, 1997, now U.S. Pat. No.5,897,880, which is a continuation-in-part of U.S. patent applicationSer. No. 08/536,750, filed Sep. 29, 1995, now abandoned, the entirecontents of both of which are hereby incorporated in their entirety.

FIELD OF THE INVENTION

This invention relates to the preparation of a transdermal deliverysystem. The preparation is designed to deliver therapeutic levels of adrug to specific sites below the dermal level of the skin including, butnot limited to, knees, ankles, hands, feet and neck.

DESCRIPTION OF THE PRIOR ART

Over the years, methods have been developed to achieve the efficientdelivery of a therapeutic drug to a mammalian body part requiringpharmaceutical treatment. Use of an aqueous liquid which can be appliedat room temperature as a liquid but which forms a semi-solid gel whenwarmed to body temperature has been utilized as a vehicle for some drugdelivery since such a system combines ease of application with greaterretention at the site requiring treatment than would be the case if theaqueous composition were not converted to a gel as it is warmed tomammalian body temperature. In U.S. Pat. No. 4,188,373, PLURONIC®polyols are used in aqueous compositions to provide thermally gellingaqueous systems. Adjusting the concentration of the polymer provides thedesired sol-gel transition temperature, that is, the lower theconcentration of polymer, the higher the sol-gel transition temperature,after crossing a critical concentration minimum, below which a gel willnot form.

In U.S. Pat. Nos. 4,474,751 and 4,478,822 drug delivery systems aredescribed which utilize thermosetting gels; the unique feature of thesesystems is that both the gel transition temperature and/or the rigidityof the gel can be modified by adjusting the pH and/or the ionicstrength, as well as by the concentration of the polymer.

Other patents disclosing pharmaceutical compositions which rely upon anaqueous gel composition as a vehicle for the application of the drug areU.S. Pat. Nos. 4,883,660; 4,767,619; 4,511,563; 4,861,760; and5,318,780. Thermosetting gel systems are also disclosed for applicationto injured mammalian tissues of the thoracic or peritoneal cavities inU.S. Pat. No. 4,911,926.

Ionic polysaccharides have been used in the application of drugs bycontrolled release. Such ionic polysaccharides as chitosan or sodiumalginate are disclosed as useful in providing spherical agglomerates ofwater-insoluble drugs in the Journal of Pharmaceutical Sciences, Volume78, Number 11, November 1989, Bodmeier et al. Calcium alginate gelformulations have also found use as a matrix material for the controlledrelease of herbicides, as disclosed in the Journal of ControlledRelease, (1986), pages 229-233, Pfister et al.

In U.S. Pat. No. 3,640,741, a molded plastic mass composed of thereaction product of a hydrophilic colloid and a cross-linking agent suchas a liquid polyol, also containing an organic liquid medium such asglycerin, is disclosed as useful in the controlled release of medicationor other additives. The hydrophilic colloid can be carboxymethylcellulose gum or a natural alginate gum which is cross-linked with apolyol. The cross-linking reaction is accelerated in the presence ofaluminum and calcium salts.

In U.S. Pat. No. 4,895,724, compositions are disclosed for thecontrolled release of pharmacological macromolecular compounds containedin a matrix of chitosan. Chitosan can be cross-linked utilizingaldehydes, epichlorohydrin and benzoquinone.

In U.S. Pat. No. 4,795,642, there are disclosed gelatin-encapsulated,controlled-release compositions for release of pharmaceuticalcompositions, wherein the gelatin encloses a solid matrix formed by thecation-assisted gellation of a liquid filling composition incorporatinga vegetable gum together with a pharmaceutically-active compound. Thevegetable gums are disclosed as polysaccharide gums such as alginateswhich can be gelled utilizing a cationic gelling agent such as analkaline earth metal cation.

While the prior art is silent with respect to aqueous drug deliveryvehicles and isotonicity thereof, osmotic drug delivery systems aredisclosed in U.S. Pat. No. 4,439,196 which utilize a multi-chambercompartment for holding osmotic agents, adjuvants, enzymes, drugs,pro-drugs, pesticides, and the like. These materials are enclosed bysemipermeable membranes so as to allow the fluids within the chambers todiffuse into the environment into which the osmotic drug delivery systemis in contact. The drug delivery device can be sized for oral ingestion,implantation, rectal, vaginal, or ocular insertion for delivery of adrug or other beneficial substance. Since this drug delivery devicerelies on the permeability of the semipermeable membranes to control therate of delivery of the drug, the drugs or other pharmaceuticalpreparations by definition, are not isotonic with mammalian blood.

To date prescription pain and antiinflammatory medications which havebeen formulated for topical use have not been approved for sale in theUnited States. This is due to their lack of efficacy and a formulationfailure to demonstrate measurable amounts of drug in the blood and urineof patients treated with these preparations. Thus proof of their abilityto be transdermally transported through the skin has not beensuccessful.

In contrast, over-the-counter drugs which include counter-irritants suchas menthol, eucalyptus, and camphor are sold for mild relief of minorproblems. These products are designed to counter-irritation and are notintended for deep penetration of tissue structures below the skin,namely into areas which include joints, ligaments, tendons andcartilage. The over-the-counter drugs described above may be purchasedwithout prescription.

A need thus exists for the administration of active therapeutic agentsthat can be applied topically and transported through the skin.

SUMMARY OF THE INVENTION

The present invention relates to the formation of a stable, sterilegelled composition and its use in treating acute or chronic conditions.More particularly, this invention relates to a stable, sterilizedcomposition, optionally containing a therapeutic drug, which comprises:a polymer matrix composed of a highly negative charged polymer materialwhich may be selected from the group consisting of polysulfatedglucosoglycans, glycosaminoglycans, mucopolysaccharides and mixturesthereof, and a nonionic polymer which may be selected from the groupconsisting of carboxymethylcellulose sodium, hydroxyethyl cellulose,hydroxypropyl cellulose, and mixtures thereof.

Another embodiment of this invention involves a method for the treatmentof a condition in animals, which comprises topically applyingtherapeutically effective doses of a gelled suspension of a compositioncomprising an optional drug within a polymer matrix which is suspendedin a liquid medium. Preferably, one of the polymer materials has a meanaverage molecular weight below about 800,000, and the other polymer is anonionic cellulose derivative. The present invention utilizes a novelcombination of polymers each having a specific ionicity. Morespecifically, the polymers used in the formulation are of two basictypes: those which have a strong negative charge, and those which arenon-ionic or have no charge attached to them.

An alternative embodiment of the invention involves a process for theuse of a composition as a medical device, for drug delivery, theapplication of a diagnostic agent, or the prevention of post operativeadhesions. This process involves topically administering to a mammal anaqueous gelled composition containing a polymer matrix composed ofnegatively charged polymers blended with nonionic polymers.

An additional embodiment involves the preparation of an antiarthriticgelled composition which comprises an active NSAID drug dispersed withina matrix containing a negative charged polymer having a mean averagemolecular weight between about 650,000 and 800,000 blended with anonionic polymer, wherein the molar ratio of the charged polymer to thenonionic polymer is 1:0.5 to 4 and the negative charged polymer ispresent in amounts of about 2.0% to about 3.0% by weight.

DETAILED DESCRIPTION OF THE INVENTION

It has been unexpectedly discovered that an effective therapeutic levelof a drug may be administered topically and transdermally deliveredthrough the skin into various sites where the drug is therapeuticallyeffective. In order for this to be accomplished, it has been discoveredthat the active drug must be suspended or entrapped in a speciallydesigned polymer matrix containing a specific molar ratio of negativelycharged polymers and a non-ionic polymer suspended or dissolved in waterand solubilizers.

This system is believed to form a matrix which microencapsulates,suspends, and/or entraps the active drug entity such that when it isadministered, it is slowly released into the systemic circulatory systemor muscular tissue providing a method of delivering an active drug to anaffected site in the body through the skin.

The molar ratio of the polymers present in the matrix is critical inthis invention. It has been found that molar ratios of the negativelycharged polymer to the non-ionic polymer must be from 1:0.5 to 4, andpreferably from 1:0.5 to 2.0, and most preferably from 1:0.7 to 2.5. Fortransdermal delivery of drugs, it has been found that ratios eitherhigher or lower than these levels will result in a polymer shearingeffect which produces unacceptable turbulence and air pockets in thecomposition with resulting loss of potency and efficacy. Furthermore,the solutions tend to separate and form distinct polymer layers whenionic molarity is not appropriate.

At least one of the polymers used to form the matrix of this inventionmust be sufficiently negatively charged to aid in the dispersion,encapsulation or solubilization of the drug. Particularly preferredpolymers which have mean average molecular weights below about 800,000and preferably molecular weights between 650,000 to 800,000 have beenfound acceptable to form usable polymer matrixes for transdermaldelivery. Polymers with mean average molecular weights between 700,000and 775,000 are most preferred. Polymers having molecular weights aboveabout 800,000 form solid gels in solution and are unable to serve aspart of a transdermal delivery system. Furthermore, the polymers must besterilizable and be stable during sterilization so that the polymer doesnot lose molecular weight once formulated into the final transdermaldelivery form.

Exemplary, non-limiting examples of compounds that may be used as asource of this molecular weight polymer include polysulfatedglucosoglycans, glucosaminoglycans, and mucopolysaccharides, derivativesthereof and mixtures thereof. Particularly preferred mucopolysaccharidesare chondroitin sulfate and hyaluronic acid salts. Exemplary hyaluronatesalts include sodium, calcium, potassium and magnesium salts withhyaluronate sodium being most preferred.

Hyaluronic acid (HA) occurs naturally in joint synovial fluid, where itplays a lubricating role, and may have biological activity was well. HAis a mucopolysaccharide, and may alternatively be referred to asglycosaminoglycan. The repeating unit of the hyaluronic acid molecule isa disaccharide consisting of D-glucuronic acid andN-acetyl-D-glucosamine. Because hyaluronic acid possesses a negativecharge at neutral pH, it is soluble in water, where it forms highlyviscous solutions. The D-glucuronic acid unit and N-acetyl-D-glucosamineunit are bonded through a glycosidic, beta (1-3) linkage, while eachdisaccharide unit is bonded to the next disaccharide unit through a beta(1-5) linkage. The (beta 1-4) linkages may be broken through hydrolysiswith the enzyme hyaluronidase.

A variety of substances, commonly referred to as hyaluronic acid, havebeen isolated by numerous methods from various tissue sources includingumbilical cords, skin, vitreous humour, synovial fluid, tumors,haemolytic streptocci pigskin, rooster combs, and the walls of veins andarteries. It is also being synthesized artificially and by recombinanttechnology.

Conventional methods for obtaining hyaluronic acid results with aproduct having differing properties and a wide range of viscosities.U.S. Pat. No. 2,585,546 to Hadian, discloses an example of a method forobtaining hyaluronic acid and which involves extracting acetone-washedumbilical cords with a dilute salt solution, acidifying the resultingextract, removing the clot so formed, precipitating some hyaluronic acidwith protein from the acidified extract with ammonium sulfate, agitatingthe liquid with pyridine, precipitating another fraction highlycontaminated with protein, followed by more ammonium sulfate whichforces some pyridine out of solution along with the high viscosityhyaluronic acid. The hyaluronic acid collects at the interface betweenthe two liquid phases and may be separated by filtration, centrifugationor another usual procedure. A modification of this process involves thefractionation of the acidic salt extract from umbilical cords withalcohol and ammonium sulfate. Alcohol is added to the acidic saltextract, and the resulting precipitate is removed. Solid ammoniumsulfate is added to the liquid until saturation and the solution formstwo phases with a precipitate of hyaluronic acid at the interface.

U.S. Pat. No. 4,517,296 to Bracke et al. is directed to the preparationof hyaluronic acid in high yield from Streptococcus bacteria byfermenting the bacteria under anaerobic conditions in a CO₂ enrichedgrowth medium, separating the bacteria from the resulting broth andisolating the hyaluronic acid from the remaining constituents of thebroth. Separation of the microorganisms from the hyaluronic acid isfacilitated by killing the bacteria with trichloroacetic acid. Afterremoval of the bacteria cells and concentration of the higher molecularweight fermentation products, the hyaluronic acid is isolated andpurified by precipitation, resuspension and reprecipitation.

One particular fraction of hyaluronic acid (HA) that exhibits excellentmatrix formation according to the present invention is hyaluronatesodium having a mean or average molecular weight between650,000-800,000, preferably 700,000-775,000 with a high degree ofpurity, 95-100% free, and preferably at least 98% pure, fromcontamination of related mucopolysaccharides. Furthermore, thishyaluronic acid has a sulphated ash content of less than 15% and aprotein content of less than 5%. Examples of usable base salts includethose safe from animal and human use, such as sodium, potassium,calcium, and magnesium salts or the like.

In contrast to HA, chondroitins are mucopolysaccharides comprisingrepeating units of D-glucuronic acid and N-acetyl-D-galactosamine.Chondroitin sulphates are important components of cartilage and bone andare excellent for preparing the polymer matrix herein.

The negative charged polymers are generally present in the system inamounts which enable a solid gel to be formed. Generally, gels areformed using amounts of about 2.0 to about 3.0% by weight with amountsof about 2.1 to about 2.5% by weight being preferred for use as atopical gel.

The solutions used to prepare the gels of the present invention may beprepared in a variety of ways. For example, the polymers may bedissolved in water and purified either separately or jointly and thenthe optional active drug added to the system.

A particularly preferred procedure involves separately dissolving thenonionic polymer in water and centrifuging the material to form asolution and remove impurities. This may be conveniently done atrotation speeds of 2000 rpm for times of about 30 minutes to about twohours.

In contrast, the negative charged polymer may be blended and stirred inwater until it is dissolved. This process must be done while avoidingthe formation of bubbles and while freeing the polymer of itselectrostatic activity. Furthermore, the molecular weight of the polymermust not be significantly changed during processing and as such mildprocess conditions are required. Processing conditions of 400-3000 rpmfor durations of 16-24 hours have been found acceptable to producestable solutions or gels of the charged polymer.

Conventional pharmaceutically acceptable emulsifiers, suspending agents,antioxidants (such as sodium meta-bisulfate) and preservatives (such asbenzyl alcohol) may then be added to this system. Once all thecomponents are blended together, such as by mixing 400-3000 rpm for oneto four hours, the system is filled into tubes and sterilized. Theresulting system is a clear gel which is storage stable for severalyears.

The drug may be added to the homogenous solution or gel separately oncedissolved or disbursed in water. Emulsifiers, suspending agents andpreservatives may then be added to this system. One particularlynonlimiting effective material for solubilizing water insoluble drugs ismethoxypolyethylene glycol (MPEG). Once all the components are blendedtogether, for 400-3000 rpm for 1 to 4 hours, the system is filled intotubes and sterilized. The resulting system is storage stable for severalyears.

The formulations may be used topically and also contain conventionalpharmaceutically acceptable excipients well known to those skilled inthe art, such as surfactants, suspending agents, emulsifiers osmoticenhancers, extenders and dilutants, pH modifiers as well as fragrances,colors, flavors and other additives.

As indicated above, the active drug agents may be blended with theaqueous polymer matrix at the time of manufacture. As such, the drugwhen in the form of a water-soluble solid is simply diluted withsterilized water or polymer matrix solution and prepared in gel form.

The dosage system can be formed with or without the use ofpharmaceutically acceptable preservatives. A significant advantage ofthe dosage form of the present system relates to its ability to allowthe drug to slowly diffuse through tissue when administered thusallowing for an effective therapeutic dose to be present for many house.

In this regard, it should be noted that reference to therapeuticallyeffective dose does not necessarily relate to conventional dosagelevels, but does relate to drug levels that achieve an effectivetherapeutic level at the dose employed, which may be the same level butnot at the same frequency of administration previously required fordrugs taken orally or by injection. This not only significantly reducesthe number of doses required to achieve the same effect, but it alsoreduces costs, maintenance and health hazards associated withconventional treatment therapies. Additionally, it results in immediateand continued drug release for long periods of time spanning severalhours in duration.

Doses may vary from patient to patient depending on the type andseverity of the condition being treated and the drug being administered.Generally, doses of 1 ml to 75 ml may be administered with preferreddoses using 2 to 25 ml of the gelled matrix system.

The formulations of this invention may be used to treat a variety ofmammal and animal conditions and physical states. These systems haveparticular application to pain management, namely the treatment andalleviation of pain associated with any disease, condition or physicalstate.

Without being limited to the specific pain being treated, thepreparations of this invention may treat the following nonlimitinglocations or sources of pain below the dermal level of the skin,including, but not limited to knees, ankles, hands, feet and neck.

In addition to treating disorders associated with pain below the dermallevel of the skin, the preparations of this invention may be used totreat a wide variety of dermatologic disorders. Exemplary, non-limitingdisorders include dermatitis conditions such as: Contact Dermatitis;Atopic Dermatitis; Seborrheic Dermatitis; Nummular Dermatitis; ChronicDermatitis of Hands and Feet; Generalized Exfoliative Dermatitis; StasisDermatitis; and Localized Scratch Dermatitis; bacterial infections ofthe skin, such as: Staphylococcal Diseases of the Skin, StaphylococcalScalded Skin Syndrome; Erysipelas; Folliculitis; Furuncles; Carbuncles;Hidradenitis Suppurativa; Paronychial Infections and Erythrasma;superficial fungal infections such as: Dermatophyte Infections; YeastInfections; Candidiasis; and Tinea Versicolor; parasitic infections ofthe skin such as: Scabies; Pediculosis; and Creeping Eruption; disordersof hair follicles and sebaceous glands such as: Acne; Rosacea; PerioralDermatitis; Hypertrichosis; Alopecia; Pseudofolliculitis Barbae; andKeratinous Cyst; scaling papular diseases, such as: Psoriasis;Pityriasis Rosea; and Lichen Planus; pressure sores; benign tumors andmalignant tumors.

A particularly preferred disorder to be treated are pressure sores.Factors that precipitate pressure sores include loss of pain andpressure sensations (which ordinarily prompt the patient to shiftposition and relieve the pressure) and the thinness of fat and musclepadding between bony weight-bearing prominences and the skin. Disuseatrophy, malnutrition, anemia, and infection play contributory roles. Ina paralyzed extremity, loss of vasomotor control leads to a lowering oftone in the vascular bed and a lowered circulatory rate. Spasticity,especially in patients with spinal cord injuries, can place a shearingforce on the blood vessels to further compromise circulation.

The most important of the extrinsic factors is pressure. Its force andduration directly determine the extent of the ulcer. Pressure severeenough to impair local circulation can occur within hours in animmobilized patient, causing local tissue anoxia that progresses, ifunrelieved, to necrosis of the skin and subcutaneous tissues. Thepressure is due to infrequent shifting of the patient's position;friction and irritation from ill-adjusted supports or wrinkled beddingor clothing may be contributory. Moisture, which may result fromperspiration or from urinary or fecal incontinence, leads to tissuemaceration and predisposes to pressure sores.

The stages of decubitus ulcer formation correspond to tissue layers.Stage 1 consists of skin redness that blanches or disappears onpressure; the skin and underlying tissues are still soft. Stage 2 showsredness, edema, and induration, at times with epidermal blistering ordesquamation. In stage 3, the skin becomes necrotic with exposure of fatand drainage from the wound. In stage 4, necrosis extends through theskin and fat to muscle; further fat and muscle necrosis characterizesstage 5. In stage 6, bone destruction begins, with periostitis andosteitis, progressing finally to osteomyelitis, with the possibility ofseptic arthritis, pathologic fraction and septicemia.

The best known treatment for pressure sores is prevention. Pressure onsensitive areas must be relieved. Unless a full flotation bed (waterbed) is used to provide even distribution of the patient's weightthrough hydrostatic buoyancy, the bedridden patient's position must bechanged at least once every 2 hours until tolerance for longer periodscan be demonstrated (by the absence of redness). Air-filledalternating-pressure mattresses, sponge-rubber "egg-crate" mattresses,and silicone gel or water mattresses decrease pressure on sensitiveareas but do not negate the need for position changes. A turning(Stryker) frame facilitates turning patients with cord injuries.Protective padding (eg, sheepskin or a synthetic equivalent) at bonyprominences should be used under braces or plaster casts, and atpotential pressure sites a window should be cut out of the cast. Awheelchair patient must be able to shift his position every 10 to 15minutes even if he is using a pressure-relieving pillow. Otherwise,patients in chairs may be more likely to have pressure sores than thosewho are in bed.

The major problem in treating decubitus ulcer is that the ulcer is likean iceberg, a small visible surface with an extensive unknown base, andto date there is no good method to determine the extent of tissuedamage. Ulcers that have not advanced beyond stage 3 may healspontaneously if the pressure is removed and the area is small.

Stage 4 ulcers require debridement; some may also require deepersurgery. When the ulcers are filled with pus and necrotic debris,application of dextranomer beads or other and newer hydrophilic polymersmay hasten debridement without surgery. Conservative debridement ofnecrotic tissue with forceps and scissors should be instituted. Somedebridement may be done by cleansing the wound with 1.5% hydrogenperoxide. Wet dressings of water (especially whirlpool baths) willassist in debriding. The granulation that follows removal of necrotictissue may be satisfactory for skin grafts to cover small areas.

More advanced ulcers with fat and muscle involvement require surgicaldebridement and closure. Affected bone tissue requires surgical removal;disarticulation of a joint may be needed. A sliding full-thickness skinflap graft is the closure of choice, especially over large bonyprominences (eg, the trochanters, ischia, and sacrum), since scar tissuecannot develop the tolerance to pressure that is needed.

For spreading cellulitis, a penicillinase-resistant penicillin or acephalosporin is necessary.

Many new dressings and topical agents are being tested and madeavailable for use. No one powder, gel, or dressing is universallysuperior. The subject is complex; ie, some are wet and lead toPseudomonas infection if used too long, others are painful, all areexpensive, and some are of little value.

Use of the present formulations either alone or in combination withvarious therapeutic agents overcomes all of these prior artdeficiencies.

It has also been unexpectedly found that when the system is administeredin a repetitive manner, once the effects of the active drug are reducedin intensity or effectiveness, such repeat treatments may result in asynergistic effect by enhancing the initial term of relief to a periodwhich exceeds the initial time of relief. This is also experienced onsubsequent treatments. In this way, the present formulations are able toextend relief or treatment from normally several hours to at leastseveral days of relief. The use of repeat applications enhances drugrelease which significantly reduces drug dependence. It also results inthe relief of continued tissue damage and may even assist in tissuerepair.

Regardless of the route of administration elected, the formulations ofthe present invention are formulated into pharmaceutically acceptabledosage forms by conventional methods known in the pharmaceutical art.

As discussed above, an effective but nontoxic amount of the system isemployed in treatment. The dose regimen for administering drugs ortreating various conditions, such as pain as described above, isselected in accordance with a variety of factors including the type,age, weight, sex, and medical condition of the subject, the severity ofthe pain, the route of administration and the particular complex orcombination of drugs employed. Determination of the proper dose for aparticular situation is within the skill of the art. Generally,treatment is initiated with smaller dosages which are less than theoptimum doses of the compound. Thereafter, the dose is increased bysmall increments until the optimum effect under the circumstances isreached. For convenience, the total daily dosage may be divided andadministered in portions during the day if desired. Generally, amountsof drug may vary from 0.0001% to about 75% by weight of the system whenusing topically with 2 to 25 ml concentrations and preferably in 3 to 10ml amounts.

The formulations of this invention are particularly useful in theadministration of drugs that could be previously administered onlyorally.

The importance of this invention becomes apparent when one considers theside-effects associated with conventional, oral drugs for treatingosteoarthritis, including NSAIDs such as diclofenac.

Typically, NSAIDs have been known to produce gastric and intestinalirritation. In addition, scarring and ulceration of the intestinal tractis quite common in patients on short- or long-term NSAID therapy.Unfortunately, there do not appear to be many alternatives to NSAIDtherapy, for patients suffering from extremely painful, inflammatoryconditions which may include osteoarthritis and other inflammatorydisorders. Thus, new NSAIDs are constantly entering the market place,each one, however, with the same potential to cause unpleasant and oftenserious side-effects.

The transdermal applications of NSAIDs and particularly diclofenacdescribed herein, are a much safer way of treating inflammatorydisorders including those related to osteoarthritis also known asDegenerative Joint Disease (DJD).

When a person takes an oral form of diclofenac, typically 100 mg to 150mg per day, the drug must be circulated through systemic blood and onlya small amount ends up in the specific site that is intended fortreatment, such as the knee. Individuals with osteoarthritis aregenerally treated with NSAIDs including, but not limited to, diclofenac,ibuprofen, Aspirin, etc., which as previously mentioned produce anantiinflammatory effect at the joint level. At therapeutic dosages fordiclofenac which are usually between 100 mg and 200 mg per day, morethan 50% of all treated patients will experience some form of GI(gastrointestinal) distress.

The transdermal delivery system described herein offers a majoralternative especially for those individuals who have a history ofundesirable side-effects associated with gastric and intestinalirritation. Also for those patients who have already suffered damage,including ulceration and loss of absorption from the intestinal tract,the transdermal preparations described herein present a new way ofproviding effective treatment and relief of painful symptoms. It hasbecome a common practice of rheumatologists and other specialiststreating osteoarthritic and associated disorders to use ulcer-type drugsof the H2 blocking variety including, but not limited to ranitidine(Zantac), Pepsid and cimetidine (Tagamet) by Smith Kline. The additionof these drugs to already high regimens "(polypharmacy)" of therapeuticagents is not desirable since these drugs often produce their ownundesirable side-effects. Although an occasional patient will experiencemild stomach upset from the transdermal preparation described herein,the effect is transient and of mild severity. In addition, patientstreated with the present transdermal diclofenac, find that they canfunction for longer periods of time (4 to 6 hours) and can simply applymore of the therapeutic gel to maintain a continuous reduction in painand inflammation. In this way, patients who apply the drug topically 3to 4 times a day can experience sustained around-the-clock relief.

Several attempts have been made in the past to produce effectivetransdermal preparations. These preparations have not been approved inNorth America for some drugs, like diclofenac, by the regulatoryauthorities as of this time. Some of the reasons cited are lack ofproven transdermal delivery. In the case of the current invention,transdermal delivery can be substantiated by:

1. Measurable blood levels of diclofenac.

2. Diclofenac presence in the urine of patients treated with thetransdermal drug.

3. The presence of diclofenac in synovial fluid where joints withsynovial fluid are the target sites for treatment.

4. Rapid absorption following topical administration.

5. Rapid relief of painful symptoms in a significant number of patientsalready being treated with the products.

In Europe, Voltaren cream (Ciba-Geigy) is popular for the treatment ofosteoarthritic conditions. This preparation contains diclofenac sodium.However, the manufacturers have not demonstrated to the satisfaction ofNorth American regulators proven ability for the cream to betransdermally absorbed. Amounts of diclofenac delivered by the cream areconsidered to be minimal at best.

It should be pointed out that diclofenac, as the sodium or potassiumsalt, is a benzeneacetic acid derivative, designated chemically as2-[2,6-di-chlorophenyl)amino] benzeneacetic acid, monosodium ormonopotassium salt. It is freely soluble in methanol, soluble inethanol, and practically insoluble in chloroform and in dilute acid.Diclofenac sodium is sparingly soluble in water while diclofenacpotassium is soluble in water. Diclofenac, the anion in Voltaren® andCalaflam®, is a nonsteroidal anti-inflammatory drug (NSAID). Inpharmacologic studies, diclofenac has shown anti-inflammatory,analgesic, and antipyretic activity. As with other NSAIDs, its mode ofaction is not known; its ability to inhibit prostaglandin synthesis,however, may be involved in its anti-inflammatory activity, as well ascontribute to its efficacy in relieving pain related to inflammation andprimary dysmenorrhea. With regard to its analgesic effect, diclofenac isnot a narcotic.

The current invention represents a break-through in that for the firsttime measurable, detectable levels of diclofenac can be delivered toaffected sites. For those patients who experience mild intestinaldiscomfort following administration, it is recommended that thetransdermal gel preparation described herein, be administered aftermeals.

In addition to the negatively charged polymers, the transdermal polymermatrix must contain a non-ionic polymer which facilitates in retardingthe absorption of the active drug through the skin and delays or slowsdown in animals natural absorption of the negatively charged polymer.

Without the presence of this component, the active drug would not bedelivered transdermally into the site targeted for treatment at levelswhich are therapeutically effective. In addition to the non-ionicpolymers described in this system, these materials are necessary toprovide thorough penetration of skin layers including the epidermis,dermis and fatty tissue layers. Evidence of this absorption through theskin layers and into the capillary bed and ultimately the systemicsystem is evidenced by the fact that detectable, measurable blood levelsof active drug, such as diclofenac, can be found in the urine ofpatients treated with the diclofenac transdermal preparation describedherein.

Particularly preferred nonionic polymers are cellulose derivatives andparticularly those selected from the group consisting ofcarboxymethylcellulose sodium, hydroxyethyl cellulose, hydroxypropylcellulose and mixtures thereof. These particular polymers have beenfound to possess exceptional ability to form sustained release matrixformulations when used in combination with a negatively charged polymer.Such polymers are generally employed in amounts of about 0.1% to about1.5% and preferably about 0.5 to about 1.4%. Amounts above about 1.5%result in the formation of a solid gel when used with the negativelycharged polymer. Amounts below about 0.1% have not been found suitableto prepare a storage stable product that has sustained drug release.

A particularly preferred HEC concentration is about 0.26 to about 1.0%by weight of the matrix.

A wide variety of medicaments which may be administered topically may beused in the delivery system according to this invention. These includedrugs from all major categories, and without limitation, for example,anesthetics including benzocaine, tetracaine, mepivacaine, prilocaine,etidocaine, bupivacaine and lidocaine; analgesics, such asacetaminophen, ibuprofen, fluriprofen, ketoprofen, voltaren (U.S. Pat.No. 3,652,762), phenacetin and salicylamide; nonsteroidalanti-inflammatories (NSAIDS) selected from the group consisting ofnaproxen, acetaminophen, ibuprofen, flurbiprofen, ketoprofen,phenacetin, salicylamide, and indomethacin; antibiotics includingamebicides, broad and medium spectrum, fungal medications, monobactamsand viral agents and specifically including such as erythromycin,penicillin and cephalosporins and their derivatives; central nervoussystem drugs such as thioridazine, diazepam, meclizine, ergoloidmesylates, chlorpromazine, carbidopa and levodopa; metal salts such aspotassium chloride and lithium carbonate; minerals selected from thegroup consisting of iron, chromium, molybdenum and potassium;immunomodulators; immunosuppressives; thyroid preparations such assynthetic thyroid hormone, and thyroxine sodium; steroids and hormonesincluding ACTH, anabolics, androgen and estrogen combinations,androgens, corticoids and analgesics, estrogens, glucocorticoid,gonadotropin, gonadotropin releasing, human growth hormone,hypocalcemic, menotropins, parathyroid, progesterone, progestogen,progestogen and estrogen combinations, somatostatis-like compounds,urofollitropin, vasopressin, and others; and vitamins selected fromwater-soluble vitamins such as B complex, vitamin C, vitamin B12 andfolic acid and veterinary formulations.

One particular criteria of the drug is that they must be solubilized inthe polymer matrix solution in order to be topically administered.

A particularly preferred additional use of the compositions of thisinvention include their uses as 1) a medical device, 2) for drugdelivery, 3) the application of a diagnostic agent or 4) the preventionof post operative adhesions.

The following examples are illustrative of preferred embodiments of theinvention and are not to be construed as limiting the invention thereto.All polymer molecular weights are mean average molecular weights. Allpercentages are based on the percent by weight of the final deliverysystem or formulation prepared unless otherwise indicated and all totalsequal 100% by weight.

EXAMPLE 1

This example demonstrates the formation of a transdermal nonsteroidalantiinflammatory preparation known as diclofenac which produces reliefof osteoarthritic and associated pain in areas affected by the disease.Such areas include, but are not limited to, knees, ankles, feet, back,neck, elbows, and hips.

Example 1 also demonstrates the formation of a transdermal preparationcontaining the NSAID drug when administered topically to sites affectedby rheumatic or osteoarthritic disease will have an analgesic andbeneficial effect. The onset of this beneficial effect in the form ofpain relief and reduction of inflammation occurs between 10 and 20minutes following topical administration and lasts for up to 6 hours.

The dosage range for the drug is between 2-4 ml (60 mg-120 mg) dependingon the severity and site of the affected area.

    ______________________________________                                        MATERIALS                                                                     ______________________________________                                        Diclofenac sodium    3%                                                       Sodium hyaluronate (HA)                                                                            2.3%                                                     Hydroxyethyl cellulose (HEC)                                                                       0.7%                                                     Methoxypolyethylene glycol (MPEG)                                                                  10%                                                      Benzyl alcohol       2.5%                                                     Water                Remainder                                                BATCH SIZE 1500 ml                                                            ______________________________________                                    

1. Into a sterilized glass vessel is added 1062.5 ml of sterile waterwhich is stirred at 1500 to 2000 rpm. Slowly add 34.5 grams of HA,having a molecular weight of around 700,000 to 775,000 and a puritydescribed above. Allow to stir for 16 to 20 hours until all of the HApolymer has dissolved into the water and a crystal-clear viscoussolution has formed.

2. Prepare a 0.7% solution of HEC by adding 10.5 grams of the solidmaterial under aseptic conditions to 250 ml of sterile water. Allow todissolve for 1 to 2 hours while stirring at 1500 to 2000 rpm. Add theHEC solution to the HA solution and mix for 10 to 15 hours until ahomogeneous solution is produced.

3. Carefully measure 150 ml of methoxypolyethylene glycol (MPEG) 10%into the mixture. RPM speeds should be increased for the mixture whilethis step is being performed to 2500 rpm. The resulting mixture thusformed should be allowed to mix at 2000 rpm for an additional 3 to 4hours.

4. At this point 2.5% of benzol alcohol or 37.5 ml is added to themixture. Again, the rpm speed is increased during this part of theprocedure to 2500. The mixture should be allowed to mix for 3 to 5 hoursat 2000 rpm.

5. Using safe techniques, 45 grams (3%) of the diclofenac should beslowly added to the mixture. Again the rpm speed for the purpose ofaddition of diclofenac should be increased to 2500, and the entire 45grams of diclofenac should be completed within 15 minutes.

The final mixture is clear with a slight green tint following 15 to 20hours of further mixing at 2000 rpm. The final product should betransferred, using aseptic technics, to 25 ml borasylicate glass jarswith a lined cap.

EXAMPLE 2

The formula and method of manufacture of Example 1 is repeated fordiclofenac potassium. The only difference is that MPEG is not used.

    ______________________________________                                        MATERIALS                                                                     ______________________________________                                        Diclofenac potassium                                                                              3%                                                        Sodium hyaluronate (HA)                                                                           2.3%                                                      Hydroxyethyl cellulose (HEC)                                                                      0.7%                                                      Benzyl alcohol      2.5%                                                      BATCH SIZE 1500 ml                                                            ______________________________________                                    

1. Into a sterilized glass vessel is added 1062.5 ml of sterile waterwhich is stirred at 1500 to 2000 rpm. Slowly add 34.5 grams of HA,having a molecular weight of around 700,000 to 775,000 and a puritydescribed previously. Allow to stir for 16 to 20 hours until all of theHA polymer has dissolved into the water and a crystal-clear viscoussolution has formed.

2. Prepare a 0.7% solution of HEC by adding 10.5 grams of the solidmaterial under aseptic conditions to 250 ml of sterile water. Allow todissolve for 1 to 2 hours while stirring at 1500 to 2000 rpm. Add theHEC solution to the HA solution and mix for 10 to 15 hours until ahomogeneous solution is produced.

3. At this point 2.5% of benzol alcohol or 37.5 ml is added to themixture. Again, the rpm speed is increased during this part of theprocedure to 2500. The mixture should be allowed to mix for 3 to 5 hoursat 2000 rpm.

4. As described above, using safe techniques, 45 grams (3%) of thediclofenac is slowly added to the mixture. Again the rpm speed for thepurpose of addition of diclofenac should be increased to 2500, and theentire 45 grams of diclofenac should be completed within 15 minutes.

The final mixture is clear with a slight green tint following 15 to 20house of further mixing at 2000 rpm. The final product should betransferred, using aseptic technic, to 25 ml borasylicate glass jarswith a lined cap.

EXAMPLE 3

The general manufacturing procedure of Example 1 is repeated for atopical dermalogical preparation. The main difference in composition isthe use of methylparabin as a preservative.

    ______________________________________                                        MATERIALS                                                                     ______________________________________                                        Sodium hyaluronate (HA)                                                                           2.5%                                                      Hydroxyethyl cellulose (HEC)                                                                       1.25%                                                    Benzyl alcohol      1%                                                        Methyl parabin      0.2%                                                      Water               Q.S.                                                      ______________________________________                                    

Prior to dissolving the HA into the water, methyl parabin is dissolvedand then HA added thereto. The remaining process steps of Example 1 werethen repeated.

When 3 to 5 milliliters of this formulation was applied to pressuresores 3 to 4 times daily, the tissue healed and returned to a normalcondition within 4 to 7 days.

Test Procedure I

Patient LHN's complaint is of headache and pain in the back of the neck.

History

She has been getting headaches for 30 years since she was 5-years-old.She has had several injuries in the past including being thrown down thestairs.

In 1996, it was noted that the headaches were bifrontal, sometimesbehind the eyes and also in the sides of the head and in the parietalregion. They were often associated with nausea and vomiting.

In June 1996, her headache was frontal, occipital and in the leftshoulder going down the left arm, and she also had low back ache.

Physical Examination

She was tender over the right cervical facets at 2-3, 4-5 and 5-6 and onthe left at 2-3 and the greater occipital nerve bilaterally

Diagnosis

Cervicogenic headaches.

This was confirmed by diagnostic blocks bilaterally at 2-3, 3-4 and 4-5which reduced her head and neck pain respectively of 6/10 and 10/10 to0/10.

Treatment With Diclofenac Gel

This was rubbed on the facet joint areas of the cervical spinebilaterally. The patient noticed marked decrease of pain in the neck 4to 8 hours after use.

When the gel was used 2 to 3 times daily, the generalized neck ache wasmarkedly reduced. In addition, some of her headaches were alsodecreased. It was noted that there was no skin irritation with the useof the gel.

Test Procedure II

This is a 32-year-old man who complains of headaches.

History

He complains of headaches in the right upper neck radiating to the rightparietal region, the right eye, the right temporal region. They areaching and stabbing with a severity between 6-10/10. They are alwayspresent but the severity varies. They have occurred since he had a motorvehicle accident in August 1993.

Physical Examination

Flexion normal, extension 80%, rotation right 90% and rotation left 90%.He is tender at the cervical facets of right 2-3, left 2-3 and the rightlesser occipital nerve.

Diagnosis

Cervicogenic headache.

This was confirmed by a positive response to diagnostic facet blocks atthe right 2-3 and 3-4 cervical facets.

Treatment With Diclofenac Gel

This was rubbed on the facet joint area on the right side of the neckand the patient noticed a marked decrease in pain for the next 4 to 8hours after use. When the gel was used 2 or 3 times a day, thegeneralized neck ache was markedly reduced. In addition, some of hisheadaches were also decreased.

Test Procedure III

Her complaint is of severe holo-cranial headaches.

History

She gave a history that one and one-half years ago she fell flat on herback on concrete. She has had severe headaches since then althoughearlier in her life she had headaches that were attributed to migraine.

She is 37-years-old. The headaches are biparietal, temporal, behind theeyes and alter in the day they become bioccipital. They have an achingand throbbing character. Sometimes she wakes up with a headache.

She has had some success with Fiorinal C1/2 in treating her headaches.

Physical Examination

Neck: Flexion 30%, extension 40%, right rotation 80% and left rotation70%. Tenderness of the cervical facets, right 2-3 and 3-4 and left 2-3,3-4, 4-5 and 5-6, 1+ at each.

Diagnosis

1. Cervicogenic headache.

2. Possible pre-existing migraine.

Treatment With Diclofenac Gel

This was rubbed on the facet joint areas bilaterally in the neck region.The patient noticed a marked decrease in pain in the neck for 4 to 8hours after use. When the gel was used 2 to 3 times a day, thegeneralized neck pain was markedly reduced. In addition, some of herheadaches were also decreased.

Test Procedure IV

This 52-year-old lady had a long history of:

1. Occasional headaches.

2. Occasional neck pain.

History

The patient had a long history of headaches of about 30 years duration.These were of a migrainous nature usually on the right side. Morerecently, these have been associated with neck pain.

Physical Examination

This revealed a tilt of the head to the left. With the right shoulderhigher than the left.

The facet joints at C2-3, C3-4, C4-5 and C5-6 bilaterally were verytender. However, they were particularly tender at C2-3 and C4-5 on theright.

Diagnosis

Degenerative joint disease of the cervical spine causing chronicheadaches and occasional neck aches.

Results of Treatment With Diclofenac Gel

This was used on three occasions for the neck pain. In each case, itdecreased the neck pain substantially. On two occasions, it aborted amigraine headache in its early stages.

Test Procedure V

This 47-year-old lady has a long history of:

1. Constant headaches.

2. Constant neck aches.

History

The patient has a history of 7 motor vehicle accidents. She underwentfacet rhizolysis about three years ago. This almost entirely relievedher headaches. She still however continued to have neck aches withphysical activity particularly involving the neck.

Physical Examination

This showed some limitation of flexion and extension to about 65% ofnormal. The facet joints from C2 to C6 were exquisitely tender more onthe right than the left.

Diagnosis

Degenerative joint disease of the cervical spine causing occasionalheadaches and neck aches.

Treatment With Diclofenac Gel

The diclofenac gel has successfully relieved her neck ache on threedifferent occasions. Each time the pain relief was almost 100%. Inaddition, it stopped the beginnings of a headache on each occasion.

Test Procedure VI

This 26-year-old lady has a long history of:

1. Constant neck ache.

2. Almost daily headaches.

History

The patient was thrown off a friend's shoulders while playing at aparty. She landed on her jaw and had her neck thrust backwardsviolently.

She was thought to have actually broken her jaw at the time of the fall.

She has been investigated for TMJ disorder because there is clearly someasymmetry in her face since the accident. However, the TMJ specialistfelt that there was no TMJ damage that could be found.

She also was found to have tender facet joints from C2 to C6bilaterally, and she said with her neck thrust forward and withdifficulty in flexion and extension particularly extension being onlyabout 60% of normal.

Physical Examination

This revealed tenderness over the facet joints at C2-3, C3-4, C4-5 andC5-6 bilaterally but especially on the right. And the facet joints weremore prominent on the right.

The TMJ was not especially tender to palpation.

Diagnosis

Degenerative joint disease of the cervical spine causing chronic neckaches and headaches.

Treatment With Diclofenac Gel

This was used on three occasions for severe neck pain. It decreased theneck pain by about 50%. It did not however relieve the headaches. Thepatient is now using the gel daily because she does find that it cutsdown her neck pain, and she is hoping it will cut down the headaches.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention and all suchmodifications are intended to be included within the scope of thefollowing claims.

What is claimed is:
 1. A method for treating pain in an animal for asustained period of time, which comprises:topically applying to saidanimal a gelled composition comprising a therapeutically effective doseof a drug for treating pain; said drug being uniformly distributed in apolymer matrix which is suspended in a liquid medium; wherein thepolymer matrix contains sodium hyaluronate combined with a nonionicpolymer.
 2. The method of claim 1, wherein the drug for treating pain isselected from the group consisting of anesthetics, analgesics,nonsteroidal anti-inflammatory drugs (NSAIDS), steroids, hormones,antibiotics, metal salts, minerals and combinations thereof.
 3. Themethod of claim 1, wherein the drug for treating pain is diclofenac. 4.The method of claim 3, wherein diclofenac is selected from the groupconsisting of diclofenac sodium, diclofenac potassium and combinationsthereof.
 5. A method for treating osteoarthritic pain in an animal for asustained period of time, which comprises:topically applying to saidanimal a gelled composition comprising a therapeutically effective doseof a drug for treating osteoarthritic pain; said drug being uniformlydistributed in a polymer matrix which is suspended in a liquid medium;wherein the polymer matrix contains sodium hyaluronate combined with anonionic polymer.
 6. The method of claim 5, wherein the drug fortreating osteoarthritic pain is selected from the group consisting ofanesthetics, analgesics, nonsteroidal anti-inflammatory drugs (NSAIDS),steroids, hormones, antibiotics, metal salts, minerals and combinationsthereof.
 7. The method of claim 6, wherein the drug for treatingosteoarthritic pain is diclofenac.
 8. The method of claim 7, whereindiclofenac is selected from the group consisting of diclofenac sodium,diclofenac potassium and combinations thereof.
 9. A method for treatingosteoarthritis in an animal for a sustained period of time, whichcomprises:topically applying to said animal a gelled compositioncomprising a therapeutically effective dose of a drug for treatingosteoarthritis; said drug being uniformly distributed in a polymermatrix which is suspended in a liquid medium; wherein the polymer matrixcontains sodium hyaluronate combined with a nonionic polymer.
 10. Themethod of claim 9, wherein the drug for treating osteoarthritis isselected from the group consisting of anesthetics, analgesics,nonsteroidal anti-inflammatory drugs (NSAIDS), steroids, hormones,antibiotics, metal salts, minerals and combinations thereof.
 11. Themethod of claim 9, wherein said drug is diclofenac.
 12. A method fortreating pain in an animal, which comprises:topically applying to saidanimal a gelled composition comprising a therapeutically effective doseof diclofenac uniformly distributed in a polymer matrix which issuspended in a liquid medium; wherein the polymer matrix contains sodiumhyaluronate combined with a nonionic polymer.